Cavity-assisted Dynamical Quantum Phase Transition at Bifurcation Points

TL;DR

This paper investigates how coupling a quantum many-body system to a cavity influences its dynamical quantum phase transitions, revealing cavity-induced control over adiabaticity and quasiparticle excitations, with potential implementation in superconducting circuits.

Contribution

It demonstrates how cavity-induced nonlinearity affects the dynamical quantum phase transition and adiabaticity in a coupled Ising model, offering a new control method.

Findings

Infinitesimal cavity drive causes gradual passage across critical point.

Cavity nonlinearity significantly impacts quasiparticle excitations.

Control of adiabaticity via cavity manipulation is possible.

Abstract

Coupling a quantum many-body system to a cavity can create bifurcation points in its phase diagram, where the ground state makes sudden switchings between different phases. Here we study the dynamical quantum phase transition of a transverse field Ising model coupled to a cavity. We show that an infinitesimal quench of the cavity driving at the bifurcation points induces gradual evolution of the Ising model to pass across the quantum critical point and excites quasiparticles. Meanwhile, when the driving is slowly ramped through the bifurcation points, the adiabaticity of the evolution and the number of quasiparticle excitations are strongly affected by cavity-induced nonlinearity. Introducing and manipulating cavity-induced nonlinearity hence provide an effective approach to control the dynamics and the adiabaticity of adiabatic quantum processes. Our model can be implemented with superconducting quantum circuits.